1. Field of the Invention
The present invention relates to a multi-colored image forming apparatus which provides a multi-colored copy of an original document.
2. Description of Related Arts
One type of known multi-colored image forming apparatus is disclosed in U.S. Pat. No. 3,914,043.
This invention relates to a copier capable of forming multi-colored images in a single-cycle image forming process by controlling the operational timing of a plurality of developing units each of which contain different color toners.
The single-cycle image forming process wherein the copy mode executes multi-colored image formation shall hereinafter be referred to as the "simul-color mode."
The simul-color mode is first selected by means of a simul-color color mode key. Then, the original document image region is subdivided into a plurality of smaller regions, and developing material colors are assigned to correspond to the respective subdivided smaller regions, thereby specifying the pattern of the simul-color mode.
When the copy function is executed after the simul-color mode pattern has been specified, the charging, exposure and transfer processes are all executed in exactly the same manner as in a normal copy operation. The developing process, however, is executed by switching among the developing units with specific timing in accordance with the smaller regions and the developing colors corresponding to said smaller regions.
The effect of the aforesaid process enables the multi-colored developing in a single-cycle image forming process.
As previously mentioned, setting the simul-color mode is accomplished after the simul-color mode is selected by assigning the individual small regions and the individual developing colors corresponding to said small regions.
The aforesaid small regions are subdivided by boundary lines oriented perpendicular to the document scanning direction.
A simul-color mode copy is frequently accomplished with two or three individual small regions.
Also, the developing colors corresponding to each of the small regions is generally constant.
That is, the simul-color mode pattern is most prevalent in one of the following: Patterns
&lt;1&gt; Color/Black PA1 &lt;2&gt; Black/Color PA1 &lt;3&gt; Color/Black/Color PA1 &lt;4&gt; Black/Color/Black
in the case of two small regions, or
in the case of three small regions.
Therefore, the aforesaid mode patterns &lt;1&gt; through &lt;4&gt; can be conveniently assigned by a simple key operation.
On the other hand, assigning three small regions (small regions subdivided by boundary lines perpendicular to the document scanning direction) may be accomplished, for example, as shown in FIG. 3, by providing two levers 101 and 102 in proximity to the document platen so that both said levers are adjustable to desired positions. Such an arrangement is disclosed in U.S. patent application No. 148,423 applied for by the present applicant.
The present invention is designed to eliminate the problems produced by assigning the small regions by means of the aforesaid two lever arrangement, and assigning the previously described simul-color mode patterns &lt;1&gt; through &lt;4&gt; by means of a simple key operation, or any combination thereof.
The aforesaid problems occur when a two-region mode pattern (mode pattern 1 and mode pattern 2) is specified by a key operation although three regions are specified by the aforesaid lever arrangement.